This invention relates to an improved retaining wall construction and, more particularly, to a retaining wall construction comprised of modular blocks, in combination with tie-back and/or mechanically stabilized earth elements and compacted particulate or soil.
In U.S. Pat. No. 3,686,873 and No. 3,421,326, Henri Vidal discloses a new constructional work now known as a mechanically stabilized earth structure. The referenced patents also disclose methods for construction of retaining walls, embankment walls, platforms, foundations, etc. In a typical Vidal construction, particulate earthen material interacts with elements such as elongated steel strips positioned at appropriately spaced intervals in the earthen material. The elements are attached to reinforced precast concrete panels and, the combination forms a cohesive support wall. The elements extending into the earthen works interact with soil particles principally by frictional interaction and thus act to mechanically stabilize the earthen work. The elements may also perform a tie-back or anchor function.
Various embodiments of the Vidal development have been commercially available under various trademarks including the trademarks, REINFORCED EARTH embankments and RETAINED EARTH embankments. Moreover, alternative constructional works of this general nature have been developed. By way of example and not by way of limitation, Hilfiker in U.S. Pat. No. 4,324,508 discloses a retaining wall comprised of elongated panel members with wire grid mats attached to the backside of the panel members projecting into an earthen mass. Vidal and Hilfiker disclose large precast, reinforced concrete panel members cooperative with strips, mats, etc. Vidal and Hilfiker disclose various shapes of panel members. In Vidal and Hilfiker the elements that are interactive with the earth or particulate behind the panels or blocks, are typically rigid steel strips or mats and rely upon friction and/or anchoring techniques, although ultimately all interaction between such elements and the earth or particulate is dependent upon friction.
It is sometimes difficult or not practical to work with large panel members like those disclosed in Vidal or Hilfiker inasmuch as mechanical lifting equipment is often required to position such panels. Forsberg in U.S. Pat. No. 4,914,876 discloses the use of smaller retaining wall blocks in combination with flexible plastic netting to provide a mechanically stabilized earth retaining wall structure. Using flexible plastic netting and smaller, specially constructed blocks arranged in rows superimposed one upon the other, reduces the necessity for large mechanical lifting equipment.
Others have also suggested the utilization of facing blocks of various configuration with concrete anchoring and/or frictional netting material. Among the various products commercially available is a product offered by Rockwood Retaining Walls, Inc. of Rochester, Minn. and a product offered by Westblock Products, Inc. and sold under the tradename, Gravity Stone. Common features of these systems appear to be the utilization of various facing elements in combination with backfill, wherein the backfill is interactive with plastic or fabric reinforcing and/or anchoring means which are attached to the facing elements. Thus, there is a great diversity of such combinations available in the marketplace or disclosed in various patents and other references.
Nonetheless, there has remained the need to provide an improved system utilizing anchoring and/or frictional interaction of backfill and elements positioned in the backfill wherein the elements are cooperative with and attachable to facing elements, particularly blocks which are smaller and lighter than large facing panels such as utilized in many installations. The present invention comprises an improved combination of elements of this general nature and provides enhanced versatility in the erection of retaining walls and embankments, as well as in the maintenance and cost of such structures.